This invention relates to a heat exchange system in a reactor such as a polymerization reactor.
Some polymerization reactions produce a considerable amount of heat. Heat exchange systems must be placed in the reactor to cool the contents of the reactor. A prior heat exchange system comprises top and bottom headers and a plurality of tubes extending between and connecting the headers. An axial or partially axial flow agitator with impellers produces a vertical flow pattern. It can be downward to the reactor bottom where the flow pattern turns and flows upward outside the impellers. Some flow is between the tubes and the reactor wall, and some is between the impellers and the tubes. Dead spots with low or no flow are observed in between the tubes. This cools the reactor contents excessively in these areas, leading to undesirably high viscosities of portions of the final product and a consequent adverse effect on the homogeneity of the final product. It also leads to poor heat transfer between the coolant in the tubes and the polymer solution. Further, these dead spots represent areas where mixing or blending of the reactor contents is inhibited and, hence, there is not thorough mixing of the reactants within the reactor.